1. Field of the Invention
One embodiment of the present invention relates to a semiconductor device.
Note that one embodiment of the present invention is not limited to the above technical field. The technical field of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Specific examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a light-emitting device, a power storage device, an imaging device, a memory device, a method for driving any of them, a method for manufacturing any of them, a method for inspecting any of them, or a system of any of them.
2. Description of the Related Art
In recent years, display devices have been used for various electronic devices such as television receivers, personal computers, and smart phones, and higher performance of the display devices in various aspects such as higher definition and lower power consumption has been achieved.
As such display devices, active matrix display devices in each of which a plurality of pixels are arranged in a matrix and is controlled by transistors provided in the pixels have been often used. In the active matrix display device, each pixel is controlled by a transistor, so that variation in transistor characteristics among pixels or deterioration in transistor characteristics causes variation in display among the pixels. Thus, display unevenness and image burn-in may be caused.
In an active matrix display device in which a light-emitting element is used as a display element, a driving transistor which controls current to be supplied to the light-emitting element in accordance with a video signal is provided. If at least one of the threshold voltage, the mobility, the channel length, the channel width, and the like of the driving transistor varies among pixels, luminance of a light-emitting element varies among the pixels.
As a method for preventing such variation in luminance of light-emitting elements, a method for correcting variation in the threshold voltages of driving transistors in pixels (hereinafter referred to as internal correction) has been suggested. (Patent Document 1 and Patent Document 2).
Furthermore, a method has been suggested in which the characteristics of a driving transistor is read out to the outside of a pixel and a signal for correcting variation in the characteristics of the driving transistor is input (hereinafter also referred to as external correction) (Patent Document 3 and Patent Document 4).
A data signal (also referred to as a video signal, a source signal, or the like) is supplied from a data driver (also referred to as a video signal line driver circuit, a source signal line driver circuit, or the like) to a pixel. In that case, a voltage follower circuit using an operational amplifier is used in a data driver in some cases (Patent Document 5).